Inkjet printers employing Memjet® technology are commercially available for a number of different printing formats, including home-and-office (“SOHO”) printers, label printers and wideformat printers. Memjet® printers typically comprise one or more stationary inkjet printheads, which are user-replaceable. For example, a SOHO printer comprises a single user-replaceable multi-colored printhead, a high-speed label printer comprises a plurality of user-replaceable monochrome printheads aligned along a media feed direction, and a wideformat printer comprises a plurality of user-replaceable multi-colored printheads in a staggered overlapping arrangement so as to span across a wideformat pagewidth.
Providing users with the ability to replace printheads is key advantage of the Memjet® technology. However, this places demands on the ink delivery system supplying ink to the printhead(s). For example, the ink delivery system should allow expired printheads to be de-primed before replacement so as not to cause inadvertent ink spillages and allow new printheads to be primed with ink after installation. Priming and de-priming operations generally require a pump to be incorporated into the ink delivery system.
A number of approaches towards ink delivery systems for inkjet printheads have been described in US2011/0025762; US2011/0279566; and US2011/0279562 (all assigned to the present Applicant), the contents of which are incorporated herein by reference.
The ink delivery systems described previously in connection with Memjet® printers generally comprise a closed loop system having first and second ink conduits interconnecting an ink container with respective first and second ink ports of the printhead. A reversible pump is positioned in the second ink conduit for pumping ink around the closed loop. Typically, a pinch valve is positioned on the first ink conduit for controlling the flow of ink or air through the printhead. As described in US2011/0279566 and US2011/0279562, the pump and pinch valve are coordinated to provide a multitude of priming, de-priming and other maintenance or recovery operations.
US2009/0219368 describes a printer comprising a pump and an air compliance chamber for dampening pressure fluctuations in a circulating ink delivery system. However, the air compliance chamber suffers from poor performance, because it can easily become filled with ink, for example, during transport or when the printer is tilted.
It would be desirable to provide a printer having an ink delivery system, which can dampen pressure fluctuations, such as those caused by actuation of a peristaltic pump, over the lifetime of the printer.